Geocoding involves programmatically assigning x and y coordinates (usually but not limited to, earth coordinates—i.e., latitude and longitude) to records, lists and files containing location information (full addresses, partial addresses, zip codes, census FIPS codes, etc.) for cartographic or any other form of spatial analysis or reference. Geocoding is even more broadly described as “mapping your data” in order to visualize information and explore relationships previously unavailable in strict database or spreadsheet analysis.
A centroid is a geographic center of an entire area, region, boundary, etc. for which the specific geographic area covers. Street vectors are address segments of individual streets, which may contain attributes such as address ranges. Street vectors can be used in displays of digitized computer-based street maps. Range information on street vectors is typically specified on the left and right side of each vector. They are also used for geocoding a particular address to a particular street segment based on its point along the line segment.
Geocoding is currently performed by running non-geocoded (referred to hereafter as “raw data”) information such as a list of customers through proprietary software and/or data, which performs table lookup, fuzzy logic and address matching against an entire “library” of all known or available address points or street vectors (referred to hereafter as a “georeferenced library”) with associated x, y location coordinates. If the raw data matches a point record from the georeferenced library, then the raw data is assigned the same x, y coordinates associated with the matching record from the georeferenced library. If the raw data instead matches a street vector, then the raw data is assigned interpolated x,y coordinates pair based on the x,y coordinates of the high and low address for the matched street vector in the georeferenced library.
The georeferenced library is compiled from a number of varied sources, depending on the territory, including census information, postal address information, street vectors with associated address ranges, postcode centroids and other various sources of data containing geographic information and/or location geometry. If a raw data address cannot be matched exactly to a specific library street address (known as a “street level hit”), then an attempt is made to match the raw data address to an ever decreasing precision geographic hierarchy of point, line or region geography until a predetermined tolerance for an acceptable match is met. The geographic hierarchy to which a raw data record is finally assigned is also known as the “geocoding precision.” Geocoding precision tells how closely the location assigned by the geocoding software matches the true location of the raw data.